I think Castiel ran away because the abuse from Bart became too much to handle. It could have affected his self-esteem, sense of safety, and overall quality of life, forcing him to seek a better situation elsewhere.
Maybe Castiel just couldn't take the abuse anymore and needed to escape for his own well-being.
Perhaps Naruto feels that Kushina is being overprotective. He wants to prove his independence and go on his own adventures without her constant supervision, so he decides to run away.
One possible reason could be that Naruto might be afraid of the intense training Jiraiya has in store for him. Jiraiya is known for his strict and grueling training methods, and Naruto, being young and sometimes impatient, might just want to escape that for a while.
Maybe he feels misunderstood by his family. In many Naruto stories, his family situation can be complex. If he's 'godlike', he might have powers that his family doesn't understand or fears, leading him to run away to avoid conflict or being treated differently.
Maybe he's running away from the pressure in the village. There are always high expectations on him, and he might feel suffocated and need some time alone to figure things out.
The reason why Taru ran away from home in the plague novel was not specified. However, the plot and character of the novel were important elements of the author's creation. They needed to be interpreted in conjunction with the author's writing intent and cultural background. If you have any other questions about Taru, I will try my best to answer them.
Maybe he gets help from his friends. For example, Ron and Hermione could come up with a plan. They might send him a magical object that can help him escape, like a flying broomstick that he can use to fly away from the Dursleys' house without being noticed.
Loki could enlist the help of some unlikely allies. For example, he might strike a deal with a creature from the realms outside of Asgard. In exchange for a future favor, this ally helps him escape by providing a means of transportation or a way to bypass Asgard's defenses.
Maybe he's feeling misunderstood or has some big dream he can't fulfill at home.
They might run away because they want to explore the wizarding world on their own terms. Without the restrictions of Hogwarts or the watchful eyes of the Ministry of Magic.